Field of the Invention
The disclosure relates generally to sense circuits for RRAM, and more particularly it relates to sense circuits for efficiently reading and writing a RRAM cell.
Description of the Related Art
Recently, new nonvolatile memory devices, such as a resistance random access memory (RRAM), have been proposed. A unit cell of the RRAM includes a data storage element which has two electrodes and a variable resistive material layer interposed between the two electrodes. The variable resistive material layer, i.e., a data storage material layer, has a reversible variation in resistance according to whether a filament, a conductive path or a low resistive path is formed through the resistive material layer by the electrical signal (voltage or current) applied between the electrodes.
The read operation of a RRAM device includes two opposite operations, i.e., the forward read operation and the reverse read operation, and the sense circuit of the RRAM device should be switched between the bit line and the source line for either read operation. In order to simplify the operation of the sense circuit in the forward read operation and the reverse read operation, we need an efficient sense circuit to read the logic state of a RRAM cell.